The Low End Mac Mailbag

World's Fastest G3, Core Image Unsupported in Most G4 Macs, and Other Thoughts on OS X 10.5

Dan Knight - 2007.05.17

Another half dozen readers weigh in on the pros and cons of G3 support in Leopard - and whether Core Image might be such an important technology that a lot of G4 users will be left out in the cold. - Tip Jar

The Time of the G3 Is Done?

Tim Larson says:


Tell Joseph Burke that if he has any of those B&W G3s that he thinks can't even be given away, I'd really like to have one. My main home server is a beige G3/300, and while the upgrade to a top-end (450 MHz) G3 tower would be noticeable, (to a guy on a shoestring budget) it isn't worth the $75 I see these things still selling for.


World's Fastest G3 Power Mac

Scott Cook writes in response to The Time of the G3 Is Done:

Ha, Mr. Burke just gave me a laugh. I had a 1.1 GHz G3 Yosemite and a 466 MHz G4 Digital Audio sitting side by side. My Yosemite would run circles around my Digital Audio for everything except audio/video encoding. For video encoding the G4 was over twice as fast. For audio encoding the G4 was a little faster. I mostly do audio/video now, so I just sold the G3 to my friend the other day and kept the G4.

I used to do a lot of bulk mailing to radio stations from my huge AppleWorks database. That G3 was by far the fastest computer I've ever used for doing looong mail merges in AppleWorks, which isn't AltiVec or multiprocessor aware. The Digital Audio takes at least twice as long to do the mail merge and create all the print images so I can address the envelopes.

This has to be the reason God invented computers. I can't even imagine how they used to do bulk mailing or radio servicing in the old days. I sold the G3 for $450, by the way. My friend is thrilled with it so far. I was just talking to him about it today, in fact. Apparently the world's fastest and (according to Mr. Burke) rarest G3 is still in demand? ha ha

You don't need to publish this. I just thought you might get a laugh out of it like I did.

Did I start this G3 on Leopard debate? (laugh) Sorry about that Dan!

Scott Cook
Reluctant Radio

Thanks for sharing your experience, Scott.

Those who would just as soon see Apple drop G3 support are invariably those who do high-end tasks that need the horsepower of a G4 or beyond. They fail to recognize that for a lot of things - the kind of things most of us do most of the time like email, browsing the Web, and writing - there's no significant benefit from AltiVec, dual processors, or AGP graphics. CPU speed and drive speed are more important factors.

So what compelling reason would Apple have for preventing them from running Leopard and the next versions of Mail and Safari?


Scott Cook replies:

I'm sure I needed a G4. I could have continued doing audio work with my 1,100 MHz G3, but video work was prohibitively slow, even on short shows. The G4 has truly amazing performance on video encoding compared to the G3. AltiVec is the difference, of course. Other than that, they're similar processors.

When encoding video, my 466 MHz G4 was over twice as fast as my 1,100 MHz G3. My 1,100 MHz G3 did everything except audio/video over twice as fast as my 466 MHz G4, which is right in line with the difference in processor speed. I did a very unscientific study encoding audio podcasts one night when I was bored. I encoded the same one hour MP3 audio podcast on all the different machines I had available here at that time. This is what I found:

  • 500 MHz G3 = 4.5x
  • 600 MHz G3 = 6.5x
  • 1,100 MHz G3 = 9.2x
  • 466 MHz G4 = 11.4x
  • 3,400 MHz P4 = 11.6x

The G3s behaved as I expected. The faster the processor, the faster they encoded. The G4 and P4 blew me away though. The P4 is over 7 times as fast as the G4 (clock speed) but just barely managed to squeak past it. I wasn't expecting that. I remember hearing people say the G4 was at least 7-8 times faster than the P4 for audio/video, but I confess that I never really believed it until I did this.

I wished I had the slowest G4, the 350 MHz Power Mac, to test alongside the fastest G3, the 1,100 MHz PowerLogix upgrade Power Mac. That would have been fun to see if the slowest G4 could beat the fastest G3 in audio encoding. Has anyone ever run that test? I'm quite certain the slowest G4 would beat the fastest G3 real bad at video encoding, but audio would probably be a good race.


Thanks for the additional info. AltiVec indeed makes a world of difference for audio/video work, but there are other architectural issues at work as well. The G4 has more efficient memory access when used on a motherboard that supports it, which is every G4 Power Mac except for the 350-400 MHz PCI model.

Simple math (350 x 11.4 / 466) estimates a 350 MHz G4 would score about 8.5x, so the slowest G4 Power Mac would probably be a bit slower than your 1.1 GHz upgraded G3 - but the second slowest G4 Power Mac (400 MHz) would probably outperform it.

As for comparing the G4 and P4, that's a whole 'nother story. There are not only vast architectural differences, but also different operating systems, different CPU/memory architectures, different software (iTunes for Mac and iTunes for Windows may work the same, but under the hood they are different, and iTunes for Windows may not be nearly as optimized as the Mac version), and different overall hardware (the PC may have a much slower hard drive, for instance).

Still, for this particular application, you've shown the danger of relying on MHz alone to predict how fast a computer will be: A 466 MHz G4, 3.4 GHz P4, and hypothetical 1.33 GHz G3 would all have about the same encoding speed.

Now imagine how fast a dual 1 GHz G4 system might be for the same task. And a Power Mac G5/2.5 GHz Quad. And then the 8-core 3 GHz Mac Pro. Of course, at some point you just can't read and write the files any faster....


Too Many G3 Macs in Use for Apple to Drop All Support

Alexander "Sasha" Ivanoff writes:

Dear Dan,

I am a high school student who uses a MacBook Pro. But my mom still uses an iMac (Summer 2001). Although 10.4 runs a tad bit slow on her iMac, it is still a reliable workhorse, and some 600/700 iMac G3s still go for a nice, yet small premium. Many public schools still use iMac G3s and will continue to do so for the next few years. Also remember that the iMac G3 sold until March of 2003 and the iBook G3 sold until September of 2003, which makes them only four years old for the youngest models.

I also strongly oppose Apple's strict requirements for hardware. I don't see Microsoft restricting which machines can run Vista. Theoretically you could install Vista Home Premium on an IBM ThinkPad 600, albeit it would run extremely slow.

I am also hurt that Apple stopped selling the original AirPort cards in 2004. At-home WiFi was only taking off at that time.

However, some machines are just way past their age, but it would be cool to see a Blue and White running 10.5.

That is just my argument, and I still have many of them.

Alexander "Sasha" Ivanoff


Thanks for sharing your thoughts. I agree that it's too early for Apple to stop supporting Macs they were still selling in 2003. Let's hope Apple feels the same way.

As for the original AirPort cards, the entire industry moved away from 802.11b to 802.11g and no Macs made in 2004 supported the original card, so once inventory was depleted, it made sense for Apple to discontinue it. The downside is that these cards sell for a premium - often US$70-100 - as they are the only internal option for those older Macs.

The modern alternative is a WiFi adapter that plugs into a computer's USB port, most of which don't seem to be Mac compatible, or the ethernet port, which tend to work with Windows PCs, Macs, and game consoles. Google for "wireless ethernet adapter mac" and you should find several options.


Best Use of Engineering Resources

Pete Gontier follows up on Leopard's Backward Compatibility:

I should clarify that my main point here is that the effort involved in offering Leopard for older machines is not just a matter of clicking a few check-boxes in Xcode. It's a big deal involving testing and engineering resources which could otherwise be invested in potentially more profitable activities. Whether this big deal is worth it to Apple is another question entirely.

I would argue nobody on the outside of the firewall has numbers good enough to be able to tell Apple what to do.

I would argue nobody on the outside of the firewall has numbers good enough to be able to tell Apple what to do. I don't have any problem with people trying to predict what Apple will do, but I have to draw the line at "Apple would be stupid not to..." or "Apple should..." because nobody has better numbers than those Apple has.

- Pete Gontier


You're right. We're only making educated guesses. Still, we have every right to call Apple stupid when it does something stupid - like the firmware block they installed on existing blue & white G3 Power Macs to block G4 upgrades and the changes in OS X that made it incompatible with RAM that had worked perfectly under OS 9.


Core Image Hardware Compatibility

Joseph Burke says:

You state in response to my most recent email that 16 MB graphics cards support Core Image. They do not. My Digital Audio came with an ATI Rage Pro 16 MB card, and when I would click on 'About this Mac' and then video, it said Core Image, no. When I installed my flashed Radeon 9700, it said Core Image: yes. Here is the official list of supported cards from Apple's Core Image page

Hardware Support

ATI and Nvidia logos

When a programmable GPU is present, Core Image utilizes the graphics card for image processing operations, freeing the CPU for other tasks. And if you have a high-performance card with increased video memory (VRAM), you'll find real-time responsiveness across a wide variety of operations.

Core Image-capable graphics cards include:

  • ATI Mobility Radeon 9700
  • ATI Radeon 9550, 9650, 9600, 9600 XT, 9800 XT, X800 XT
  • Nvidia GeForce FX Go 5200
  • Nvidia GeForce FX 5200 Ultra
  • Nvidia GeForce 6800 Ultra DDL, 6800 GT DDL

None of these cards was ever available with less than 64 megs and some were only available with 128 megs in Mac Edition. There are no 16 MB video cards that are Core Image capable, onboard or in a slot. The Radeon 7500 installed on the 900 MHz iBook can't do it.

I wouldn't count on the Nvidia FX Go5200 or 5200Ultra as being viable Core Image cards, either. Nvidia touted the 5200 as the only DX9 compliant chipset in it's price range at one time, but it ran so slowly that it really wasn't useful for DX9 graphics, even with 256 megs of memory. It was strictly a propaganda move to one up the Radeon 9200. It probably won't do Core Image well, either. The Go5200 chipset installed on some Apple machines also uses vampire video, which will slow performance of those machines attempting to run Core Image dependent applications even further.

Someone mentioned that the value of G3 machines will plummet if Apple drops G3 support. Can they plummet any further? You can already get G3 Power Macs about $50 shipped on eBay, less if you buy locally. I've already seen them on Freecycle. G3 iMacs aren't far behind. Only the fastest models are managing to retain any sort of resale value these days. Snow iBooks can be had for $200-$300, so most of their depreciating is already done, as well. My advice to anyone who thinks their G3 may be outdated soon is to grab a G4 Digital Audio, Quicksilver, or a Titanium PowerBook now while the prices are still falling.


You're right: No 16 MB graphics card supports Core Image. But you're wrong in claiming I said any did. What I said was:

"The fastest G3 iMac ran at 700 MHz, and the fastest iBook at 900 MHz. Each has AGP video with at least 16 MB of video memory. The iBook G3/900 even has Radeon 7500 graphics on a 2x AGP bus. Yes, it's not supported [emphasis added] by Core Image, but it works nicely with Tiger, as thousands of users will attest."

Core Image may be wonderful. I'll never know with the Radeon 9000 in my dual 1 GHz Power Mac G4. Mac OS X 10.4 runs just fine without Core Image support. For email, browsing the Web, and writing - the three tasks I do most of the time - there's no real benefit from Core Image.

Apple has nothing to gain by eliminating any and all G3 support in Leopard - and a lot of OS X 10.5 sales to lose if they do.


Core Image to Determine Leopard Compatibility

Eytan Bernet writes:

You wrote:

"You make a very important point about testing, but we can't ignore how sales of Leopard to existing Mac users impacts Apple. Piper Jaffray estimates that Apple will sell 2.6 million copies of OS X 10.5 during its first quarter and 9 million copies its first year. That points to about 3 million units sold as upgrades and represents perhaps 20-25% of Mac users who have compatible hardware.

"There are millions of G3 Macs out there running Tiger, and the people who upgraded to 10.4 two years ago are likely candidates to upgrade to Leopard later this year. Apple has to weigh the income from 1 million more copies of OS X sold against the cost of testing. I somehow can't imagine them leaving the bulk of those users behind."

I disagree that the Tiger adoption has been that great for G3s. Lots of the apps that require Tiger require a G4 or better as well (the iLife 05 suite, other than iTunes, worked mostly with only G4s - iLife 06 does not support G3s, Toast 7, let alone 8, etc.)

Add to that, people who don't buy new hardware in that many years are not about to shell out money on an OS for their aging hardware. I am sure Apple did the math and realized that for the number of people who want the G3 support, it is just not worth it....


You wrote:

"Apple would have to deliberately compile the Leopard installer to prevent it from running on a Mac without a G4 or later CPU and would also have to deliberately compile Leopard itself to require the presence of a G4 or later to keep hacks like XPostFacto from working. I can see them doing the first (and hope they won't), but can't imagine them doing the latter."

I can. So many of Leopard's new features depend on having vector units for operation. Core Animation is used throughout Leopard and is an integral part of the OS. It is nonfunctional without vector units.

Nuff said. I think the wish for Leopard to be supported on G3s needs to be nixed. Instead of arguing why it should be kept, you need to argue as to why it should not.



We've used Macs productively since 1984 without computer animation built into the operating system, and as cool as Core Animation looks, a lot of G4 Macs don't have the processing power to support it, so Apple would have to raise the bar way beyond cutting off just G3 Macs.

The question isn't which "whiz bang" technologies won't run on older Macs, but which essential technologies will. Core Animation and Core Image are not essentials.


Etyan responds:

I disagree. Not when core features of the OS (like Time Machine, for example) need to be rewritten to not use elements like Core Animation. Core Animation requires a vector unit, OS features require Core animation.


If you're correct, a lot of G4 owners are going to be left out in the cold, as lots of older G4 Macs don't have the graphics processors and video RAM to support Core Image (required by Core Animation). Here's a list of the oldest Macs that support Core Image out of the box:

This eliminates not only all G3 Macs, but all G4 iBooks over two years old, all titanium PowerBooks, first generation 12" and 17" PowerBooks, and all G4 iMacs except that 17" and 20" 1.25 GHz model. No G4 Power Macs are supported without a video card upgrade.

While the rest of us are anticipating that Leopard may support Macs introduced 4-6 years ago, making Core Image a required feature would draw the line at 2-4 year old models.

As I've said before, I don't expect Apple to write off that many Mac users when Leopard ships in October.


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Dan Knight has been publishing Low End Mac since April 1997. Mailbag columns come from email responses to his Mac Musings, Mac Daniel, Online Tech Journal, and other columns on the site.

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